For the points it gives you, Asthmatic trait is just an annoyance, it is rarely actually harmful.
Some things should drastically increase odds of asthma attack, and increase it’s severity. Like inhaling any kind of smoke, being low on stamina, and thus, running out of breath, smoking anything, being near fungal spores, catching a cold or a flu.
At the same time, if you have inhaler, asthma attacks should not wake you at night, but simply use the inhaler charge. It may be not completely realistic, but it removes good portion of unneeded annoyance.